Power factor correction in a power supply forces an input current to follow an input voltage so that any electrical load appears like a resistor. Power factor correction (PFC) converters, however, can cause hard switching instances when the MOSFET is operated under critical conduction mode (Crm) or continuous conduction mode (CCM). Hard switching causes high switching losses and reduces the efficiency of the PFC converter. The switching losses can be minimized when a drain voltage of a power MOSFET of the PFC converter is turned on at its lowest value known as a valley switching point. Although the zero current of boost inductor can be detected (ZCD), there is an inherent time delay between zero current point and the valley voltage of power MOSFET. In other words, when the zero current of the inductor is first detected, the power MOSFET's drain voltage is not at the valley switching point.